Antibiotics, such as tetracyclines, are used as overall health promoters in livestock animals, and for therapeutic and prophylactic disease control in animals such as poultry and livestock, companion animals, and so forth. Such antibiotics are typically formulated in an animal medicated feed premix or animal feed supplement containing the antibiotic and an edible carrier. These premixes or animal feed supplements may then be mixed with a sufficient quantity of an appropriate animal feed to provide a final animal feed formulation having the desired level of active compound in the feed.
One problem associated with animal feed medication pertains to the loss of finely divided antibiotics through dusting and electrostatic adhesion of finely divided particles, which may cause a lack of uniformity in drug concentrations in the final feed from batch to batch. Dust particles that adhere to feed mills or other feed processing equipment or that may be carried away in dust collection system may contain significant quantities of the active ingredient. This may cause the feed mixtures to have a lower concentration of the medicament desired. Dust adherent to the feed processing equipment and dust collected in a dust collection system that is recycled in subsequent batches may cause the feed mixtures produced in later batches to have a higher concentration of the active ingredient than desired, or may cause carry over of the drug to feed batches which are not intended to contain the drug.
Many attempts have been made to overcome the problem of dust formation in animal feed premixes and supplements. For example, it is known to add oil to reduce the dust and electrostatic adhesion in animal feed supplements. In U.S. Pat. No. 4,211,781, there is taught a process for preparing a substantially dustless carbadox animal feed premix by admixing carbadox with a non-toxic oil and an edible carrier. In U.S. Pat. No. 3,696,189, it is taught to coat the antibiotic particles of an animal feed supplement with an oil to stabilize the antibiotic against the deleterious effects of moisture or other materials contained in the animal feed supplement. It is also known to add oil as a pharmaceutically and nutritionally acceptable carrier or diluent for animal feed supplements.
Another attempt to overcome the problem of feed batch cross contamination is taught in U.S. Pat. No. 4,447,421, directed to a process for making particulated (granulated) animal feed premixes by combining the drug with a compressible carrier, followed by blending the mixture, compressing the mixture, and granulating the composition. Although this process has been somewhat successful in reducing dusting, it would be desirable to reduce dusting further. Attempts have been made to do so through the addition of oil, however, it has been found that the addition of oil causes a loss of structural integrity of such compressed formulations and causes a separation of the drug from the carrier.
In another attempt, a substantially dustless solid animal feed premix is taught in U.S. Pat. No. 6,761,899 which is prepared by combining fermentation solids resulting from reduction of a fermentation broth including a fermentation medium in which an organism was cultured for producing the antibiotic, said fermentation solids having an antibiotic activity sufficient to ameliorate an antibacterial infection to treat an animal. This process requires the handling of live cultures and 4-5 days of processing to produce a dry material suitable for sizing before use.